Personal Relationships, 8 (2001), 425-455. Printed in the United States of America. Copyright 0 2001 ISSPR. 1350-4126/01$9.50

The desire for sexual variety as a key to understanding basic human mating strategies

DAVID l? SCHMITT,a TODD K. SHACKELFORD! JOSHUA DUNTLEY,c WILLIAM TOOKE,d AND DAVID M. BUSS “Bradley University, ’Florida Atlantic University, ‘University of Texas at Austin, and ‘State University of New York at Plattsburgh

Abstract Different authors have proposed competing evolutionary theories of human mating. Some argue that both sexes are designed to pursue a singular long-term mating strategy. Others contend that both sexes are designed to function as essentially multiple maters. Sexual Strategies Theory (SST; D.M. Buss & D.P. Schmitt, 1993), in contrast, proposes that men and women have evolved short-term and long-term mating strategies that are pursued differently by each sex depending on theoretically derived dimensions of context. According to SST, the sexes tend to differ in the nature and prominence of the short-term component of human mating-particularly the short-term desire for sexual variety. The current research was designed to test competing empirical predictions from these contrasting theories by focusing on sex differences in the desire for sexual variety. Study 1 (N = 1,049), consisting of five separate samples, found large and consistent sex differences in the desire for short-term sexual variety, even after employing statistical methods to control for skewed distributions and statistical outliers. Study 2 (N = 192) confirmed the results of Study 1 using an older, more mature sample. Study 3 (N = SO) again replicated these sex differences using an observer-based method of inquiry. Study 4 (N = 167) found evidence that short-term mating was unrelated generally to psychological dysfunction and may be related to mentally healthy personality characteristics in men. Discussion focuses on the viability of pluralistic compared with monomorphic evolutionary theories of human mating strategies.

The fundamental nature of human mating diverse mating strategies? And do men and strategies has been the focus of intense women differ fundamentally in the tempo- theoretical and empirical scrutiny over the ral component of their mating strategies? past decade (e.g., Buss & Schmitt, 1993; The debate about the temporal dimen- Gangestad & Simpson, 2000; Kenrick, sion of mating has crystallized into several Sadalla, Groth, & Trost, 1990).Although re- basic positions. According to one evolu- searchers have converged on many of the tionary theorist, humans are designed to be basic outlines of mate selection criteria, far serial monogamists: “Human pair-bonds more debate has centered on the temporal originally evolved to last only long enough dimension of mating. Are humans funda- to raise a single dependent child through mentally monogamous, designed to seek a infancy, the first 4 years . . . those first homi- singular partner for a lifetime? Or are hu- nid forebears who remained together until mans essentially promiscuous, designed to their child was weaned survived dispropor- seek multiple short-term partnerships? Do tionately, selecting for serial monogamy” humans have a mixed menu of temporally (Fisher, 1992, p. 154). Fisher argues that by divorcing after roughly 4 years, a man would be able to re-mate with a younger Address correspondence to David P. Schmitt, Depart- ment of Psychology, Bradley University, Peoria, IL woman of higher fertility, whereas a woman 61625, E-mail: [email protected]. would be able to re-mate with another man 425 426 D.R Schmitt et al. who provided “better protection and sup- children, given the many years of protection port” (Fisher, 1992, p. 159). Furthermore, and assistance human offspring typically “with each new pair-bond social ties would need to thrive: “It is doubtful that a short- be extended to a band nearby” (Fisher, term bonding mechanism, or serial monog- 1992, p. 161). amy, would have been selected for” (p. 251). Fisher’s theory of an evolved serial mo- The Zeifman-Hazan theory, therefore, con- nogamy strategy is proposed to be equally trasts markedly with Fisher’s serial monog- optimal for both sexes. One problem with amy theory. this theory is that a woman’s reproductive A clear implication of the Zeifman- value declines more than a man’s with in- Hazan theory is that deviations from secure creasing age (Symons, 1979;Williams, 1975). attachment represent evolutionary or ulti- Moreover, the presence of children gener- mate-level maladaptations rather than vi- ally makes it more difficult for a woman to able alternative mating strategies. Indeed, mate with increasingly better partners be- insecure attachment experiences are re- cause children are typically viewed by pro- lated to a broad range of psychological dys- spective partners as a cost, not a benefit, on function (Dozier, Stovall, & Albus, 1999). the mating market (Daly & Wilson, 1988). Moreover, “dysfunctional early attachment Fisher responds to these points by suggest- relationships [those that are not secure] are ing that infrequent interband contact would a common precursor of adult sexual devi- have limited a woman’s ability to acquire a ance” (Zeifman & Hazan, 1997, p. 255). “prime mate” on her first mateship, and Thus, this view holds that our most basic hence over time contact with other bands human mating strategy consists of secure may have afforded opportunities to “marry romantic attachment and relatively long- up.” Furthermore, she notes that an existing term monogamy. Deviations from this pat- man’s mate value might decline precipi- tern are seen as ultimately maladaptive in tously due to injury, opening up to women posing risks to children in the evolutionary the advantages of “trading up.” Serial mo- currencies of survival and reproduction and nogamy, in roughly 4-year intervals, thus are proximately maladaptive in causing ro- represents one theoretical position on the mantic relationship instability and general temporal dimension of human mating strat- psychological dysfunction (Hazan & Zeif- egy design. man, 1999). A second theory is that humans are fun- Miller and Fishkin (1997) concur with damentally designed for life-long romantic Zeifman and Hazan’s theory but are even relationships, and any deviation from long- more explicit in claiming that short-term term pair-bonding would represent a dis- mating and variations from secure attach- ruption of our natural mating psychology. ment represent early developmental fail- Zeifman and Hazan (1997)’ for example, ures: “It seems that a propensity to spend argue that human mating psychology has more of one’s time seeking short-term rela- co-opted evolved attachment mechanisms. tionships rather than long-term ones may Adult attachment, in this view, is designed have been a ‘fallout’ of a failure to interface to provide mutual support and protection, with human’s adapted for social environ- cement the bond between a man and a ment (e.g., responsive paternal and maternal woman, and enhance the survival and re- caregivers)” (p. 228). Short-term mating is production of children. Without the force of seen as a perturbation or deviation from the attachment, they argue, mating partnerships preferred species-typical pair-bonding strat- would become unstable. Men, in particular, egy, resulting from unnatural and recent might stray from the bonds of long-term sources of variability in parental care that mating, imperiling the survival and repro- emerged only “after the Pleistocene era” (p. duction of the children. According to Zeif- 228). They contend “our current biological man and Hazan, any tendency toward short- design-rooted in our Pleistocene gatherer- term mating would severely jeopardize hunter roots-strongly favors relatively en- Desire for sexual variety 427 during relationships and few sex differences proposed to differ between the sexes, some- in mating strategies” (p. 197).Thus, ancestral times in rather profound ways. In long-term men and women alike are believed to have mating, for example, the sexes are proposed normatively developed secure attachments to differ in several of the key qualities with parents and subsequently pursued desired in a partner, with men placing a long-term pair-bonds as adults. greater value on cues to fertility (age, fea- At the other end of the temporal spec- tures of physical appearance) and fidelity trum of theoretical positions are those who (signals of sexual faithfulness) and women argue that men and women are fundamen- placing a greater value on resources and tally and equally designed to be short-term men’s long-term commitment to them and maters. Silverstein (1996) argues that both their children (Ellis, 1992; Schmitt & Buss, men and women are essentially promiscu- 1996). ous, drawing special attention to species The short-term mating strategy, too, is closely related to humans such as bonobo proposed to differ between the sexes. For chimpanzees, which are highly indiscrimi- women, short-term mating may have nate in their mating practices. However, evolved as a strategy to develop special beyond phylogenetic comparisons few protective friendships with certain males theoretical arguments or human empirical (Smuts, 1985), to gain access to males with evidence are provided to support this posi- high quality or diverse genes (Gangestad & tion (see also Hrdy, 1981). Simpson, 1990; Smith, 1984), to gain access The final theoretical position on the tem- to some males with many resources (Sy- poral spectrum of mating design involves mom, 1979), or to gain access to many pluralistic approaches to human mating males with some resources (Hrdy, 1981). strategies (e.g., Gangestad & Simpson, Women may also seek short-term mates as 2000). These approaches tend to view the a means of finding a higher-quality mate in many forms of human mating, including case their current partners someday need those linked to both secure and insecure at- replacement (Schmitt & Buss, 2001; Smith, tachment, as potentially viable reproductive 1984). Thus, for women the adaptive bene- strategies (Belsky, 1997; Chisholm, 1996). fits of short-term mating may result from a They tend also to use a behavioral ecologi- relatively discriminating process of care- cal perspective, emphasizing that varying fully identifying and selectively mating with environments during an individual’s devel- men who possess superior levels of status, opment naturally induce adaptive shifts in resources, or genetic quality (Greiling & mating strategies and behaviors (Belsky, Buss, 2000). Steinberg, & Draper, 1991;Lancaster, 1989). In contrast, for men the adaptive bene- We will focus in this article on one version fits of short-term mating likely followed of the pluralistic perspective called Sexual from more indiscriminate desires, particu- Strategies Theory (SST) that has provoked larly the indiscriminate desire for sexual va- theoretical debate about the fundamental riety (Symons, 1979). This tenet stems from nature of human mating strategies. the selective consequences that follow from According to SST (Buss & Schmitt, a large and fundamental sex difference in 1993),men and women have evolved a tem- minimum obligatory parental investment poral menu of mating alternatives, includ- (Trivers, 1972). Whereas it takes a woman a ing both short-term and long-term sexual substantial 9-month investment of internal strategies. Each sexual strategy is thought fertilization and gestation to produce a to harness certain adaptive desires that lead child, a man’s minimum investment can be (or would have led in our ancestral past) to as small as a single act of sex. The direct increased reproductive success in a given reproductive benefits associated with mul- selective environment. A central feature of tiple mating via sexual variety, therefore, SST is that the evolved psychological un- would have been considerably higher for derpinnings of these mating strategies are human males than for females, all else be- 428 D. l? Schmitt et al. ing equal (see also Bjorklund & Shackel- of assumption of normality” (p. 220). Rather ford, 1999). than natural variation in the desire for sex- Buss and Schmitt (1993) used this line of ual variety residing both within each sex and reasoning to make three key predictions between the sexes, Miller and Fishkin hy- concerning sex differences in short-term pothesize “few sex differences in mating mating psychology. Prediction 1: Men will strategies” (p. 197). Most men and women express greater desire for, or interest in, are assumed to be fundamentally alike in short-term mates more than women. Predic- their mating desires, with both wanting “one tion 2: Men will prefer a larger number of sex or two” partners for a lifetime: “In fact, we partners over varying time intervals than would expect that whereas most men and women. Prediction 3: Men will require less women would be seeking a long-term mate, time to elapse before consenting to sex than their desire to seek a short-term mate would will women. With each prediction, SST as- be minimal” (p. 224). serts that the design of men’s short-term This point of contention is pivotal for dis- mating psychology-due to a selective his- criminating among different evolutionary tory of lower obligatory parental invest- theories of human mating and romantic re- ment-should be influenced by the desire lationships. Any theory that portrays hu- for sexual variety more than the design of mans as designed to be exclusively long- women’s short-term mating psychology. term strategists would forecast very few Note that these predictions do not imply individuals to express short-term desires for that all men should pursue short-term mat- sexual variety. Only those unfortunate few ing as a sole, or even primary, reproductive who have experienced developmental at- strategy. SST clearly delineates the many tachment failures would forsake monoga- adaptive benefits for men that accrue from mous long-term mating as adults and en- long-term mating. Nor does this series of gage in short-term sexual relationships. predictions imply that women should com- Even then, any short-term maters would pletely refrain from seeking short-term likely display residual expressions of psy- mating relationships. Women may gain sig- chological dysfunction. Theories that view nificant adaptive advantages by pursuing humans as essentially promiscuous would situationally contingent short-term mate- expect nearly all people to report a potent ships (Greiling & Buss, 2000; Lancaster, desire for sexual variety. Any reported lack 1989). Instead, SST forecasts that men will of short-term desires might be explained as more actively desire brief mating relation- resulting from religious, legal, or cultural ships, prefer larger numbers of partners, and traditions designed to counter our natural require less time before sex than women be- tendency toward promiscuity. Furthermore, cause men, but not women, possess an adap- all monomorphic theories of human sexual- tive short-term desire for sexual variety. ity-whether most people are expected to Although a voluminous body of empiri- be monogamous or promiscuous-would cal evidence has cumulated supporting the logically predict no significant sex differ- basic tenets of SST (see Buss, 1998 for a ences in the desire for sexual variety be- review), this suite of hypothesized sex dif- cause all humans should be designed to pur- ferences in the desire for sexual variety has sue the same basic mating strategy. Of remained hotly disputed. Miller and Fishkin course, it is not the case that monomorphic (1997), for example, contend that findings of theories anticipate all people to be exactly significant mean-level sex differences in the identical in manifest or phenotypic sexual desire for a large number of sex partners are behavior, but such theories produce the rea- misleading due to the presence of male out- soned expectation that differences in de- liers. In their attempt to replicate Buss and sires for sexual variety both between and Schmitt’s (1993) original findings, Miller within the sexes “would be minimal” due to and Fishkin note: “These variables were a uniform genotypic design of the human highly skewed resulting in severe violations mind. Desire for sexual variety 429

In contrast, pluralistic evolutionary ap- was 21.3 years. Members of all samples proaches like those of Belsky (1997) and participated in the current study for extra Chisholm (1996) would predict substantive credit in psychology courses, and they were adaptive variation exists within each sex in primarily middle-class and Caucasian. the desire for short-term opportunistic mat- ing. Depending on their own mate value, the Procedure. The Undergraduate sample local sex-ratio, and other ecological sources completed questionnaires adapted specifi- of information (see Gangestad & Simpson, cally from Buss and Schmitt (1993). All par- 2000), some men and women should pursue ticipants were presented with a packet of frequent short-term mateships, whereas measures entitled “The Anonymous Ques- others in different situations are expected tionnaire Study.”The first page of the packet to pursue long-term mating strategies. Plu- contained blanks on which participants ralistic approaches such as SST (Buss & were to provide their age and sex, and it Schmitt, 1993) would further predict that contained the following instructional set: functional sex differences in short-term “Znstructions: This questionnaire is entirely mating would be driven by the adaptive voluntary. All your responses will be kept male desire for sexual variety. Thus, the goal confidential and your personal identity will of the current set of studies was to pit the remain anonymous. No identifying informa- predictions from the various temporal mat- tion is requested on this survey, nor will any ing theories against each other, with a spe- such information be added later to this sur- cial focus on sex and individual differences vey. If any of the questions make you un- in the desire for sexual variety. comfortable, feel free not to answer them. You are free to withdraw from this study at any time for any reason. This questionnaire Study The Desire for Sexual Variety 1: should take about 5 minutes to complete. among College Undergraduates Thank you for your participation.” The first questionnaire adapted from Method Buss and Schmitt (1993) was used to test Sample. The participants in this study were Prediction 1 and will be referred to as the comprised of five samples. The first sample “Currently Seeking” measure. This meas- was obtained from an archival data set origi- ure asked participants: “Please rate the de- nally collected by Buss and Schmitt (1993). gree to which you are currently seeking a This sample included 75 men and 73 women long-term mating partner (i.e., a marriage from a large public university in Michigan; partner) and short-term mating partners the average age of participants was 18.7 (i.e., one-night stands, brief affairs, etc.) by years. We will refer to this data set as the circling one number on each of the follow- “Original” sample. ing 7-point scales.” This instructional set The second sample included 103 men was followed by two Likert-type scales and 214 women from a medium-sized pri- ranging from 1 (currently not at all seeking) vate university in Illinois. The third sample to 7 (currently strongly seeking), one scale included 120 men and 268 women from a for rating “Long-Term Mating Partner public university in Florida. The fourth sam- Seeking” and one scale for rating “Short- ple included 81 men and 137 women from a Term Mating Partner Seeking.” large public university in Texas. The fifth The second questionnaire adapted from sample included 35 men and 91 women Buss and Schmitt (1993) was used to test from a public university in New York. The Prediction 2 and will be referred to as the second through fifth samples were com- “Number of Partners” measure. This meas- bined to form what will be referred to as the ure instructed participants to fill in open- “Undergraduate” sample. The Undergradu- ended blanks with their responses concern- ate sample had a total of 339 men and 710 ing: “Ideally, how many different sex women, and the average age of participants partners would you like to have . . .” over 430 D. R Schmitt et al. different periods of time ranging from 1 seeking among men and women in the larger Month to “your remaining lifetime.” Un- and more diverse Undergraduate sample. like the original measure from Buss and The original sex difference in short-term Schmitt, participants in this study also re- mate seeking was replicated in the Under- sponded regarding how many different graduate sample, with men’s level of seeking partners they would ideally like to have sex short-term mates (M = 3.4, SD = 2.1) sig- with in the next day and in the next week. nificantly higher than women’s (M = 2.2,SD The third questionnaire adapted from = 1.7),t(1035) = 10.12,~< .001. Buss and Schmitt (1993) was used to test Although no explicit predictions were Prediction 3 and will be referred to as the made about overall levels of long-term mate “Time Known” measure. This measure seeking, we also examined sex differences in asked participants to rate on a 6-point scale the tendency to seek long-term mates. In the ranging from +3 (definitely yes) to -3 Original sample, men and women were simi- (definitely not) the degree to which, “If the lar in their self-reported long-term mate conditions were right, would you consider seeking. However, in the larger Under- having sexual intercourse with someone graduate sample consisting of participants you viewed as desirable if . . .” they had from four diverse universities, we found that known that person for varying amounts of women (M = 4.5, SD = 2.1) were signifi- time ranging from 5 Years to 1 Hour. cantly higher than men (M = 3.8, SD = 2.0) Unlike the original measure from Buss and in their long-term mate seeking, (1033) = Schmitt, participants also responded to -5.04, p < .001. Buss and Schmitt (1993) time periods of 10 Years and 1 Minute. The also hypothesized that “short-term mating specific order of presentation of the three will represent a larger component of men’s measures had participants first complete sexual strategy than of women’s sexual strat- the Time Known measure, then the Num- egy.” (p. 210). We found the relative propor- ber of Partners measure, and then the Cur- tion of short-term mate seeking (short-term rently Seeking measure. mate seeking divided by the sum of short- term and long-term mate seeking) was sig- nificantly higher in men (M = .47, = .21) Results and discussion SD than women (M = .34, SD = .20), t(1031) = Do male undergraduates seek short-term 10.1241 < .OOl.This sex difference displayed mates more than female undergraduates? a moderate to large effect size (d = .65) and Prediction 1 from SST forecasts that men was also statistically significant and moder- will actively desire short-term mates more ate in size in the Original sample, t(121) = than women. To test this prediction, we 3.54,~< .001,d = .62. performed independent t-tests comparing Overall, Prediction 1 was supported in undergraduate men’s mean level of seeking the current study utilizing a larger and short-term mates with undergraduate somewhat more diverse sample than was women’s mean level of short-term seeking originally used in Buss and Schmitt (1993). as assessed by the Currently Seeking meas- From this we can conclude that, although ure. As described in Buss and Schmitt there is meaningful variation within each (1993), the Original sample included men sex, college-aged men do seek short-term who, on average, rated their current level of mates more than women. They do so on short-term seeking (M = 4.7, SD = 1.7) sig- average, and they do so proportionately. nificantly higher than did women (M = 2.9, Among evolutionary theories of human SD = 1.8),t(121) = 5.76,~< .001. To evalu- mating, pluralistic theories that predict sex ate whether this sex difference was gener- differences in the short-term desire for sex- alizable to populations other than young un- ual variety seem to most reasonably ac- dergraduate students from Michigan, we count for this pattern of results. examined the levels of short-term mate It is important to note that alternate Desire for sexual variety 431 nonevolutionary explanations of these find- and Schmitt (1993), we examined the extent ings exist, such as gender socialization and to which sex differences existed in the social-role stereotyping (e.g., Eagly, 1987). Number of Partners measure in the Under- Men may desire sexual variety and seek graduate sample. A primary criticism of the short-term mates more than women be- findings reported by Buss and Schmitt us- cause men have experienced a developmen- ing the Number of Partners measure was tal history in which they observed other that because the scales are open-ended, men preferring sexual variety, and short- some participants (particularly a few inse- term mating was seen as consistent with cure men) might respond with “extreme” their particular culture’s view of masculin- desires for large numbers of future sexual ity. Certainly, it will be important to repli- partners. These extreme responses might cate these findings across a wide range of skew the distribution of short-term desires cultures, and this research is currently un- among men as a whole and artificially in- derway. However, this form of alternate ex- flate the group mean representing the aver- planation often leaves many unanswered age man (see Miller & Fishkin, 1997). In questions, Why do men experience this form fact, Buss and Schmitt had some male par- of socialization, why do cultures define mas- ticipants report extreme desires (i.e., more culinity in this way, and why do sex-roles than 2 standard deviations above the mean) exist in the first place? Indeed, one of the and dealt with the issue by truncating all earliest critics of sex difference research re- outliers above 100 to 99. cently concluded: “The socialization ac- Although most methods of dealing with count has not proved adequate to the task outliers result in similar statistical out- of explaining gender differentiation” (Mac- comes, Rosenthal and Rosnow (1991) sug- coby, 1998, p. 9). Of course, the forces of gest a better way to handle extreme scores gender socialization likely do play an im- on open-ended scales is to use “trimmed portant role in the development of human means,” both in terms of reporting means mating tendencies. However, we feel the and when performing statistical signifi- evolutionary perspective will be essential in cance tests of differences between means fully explaining these phenomena. Only by (see also Howell, 1987; Yuen & Dixon, integrating what we know from compara- 1972). Trimmed means are created by elim- tive psychology, human ethology, and repro- inating a percentage of scores on both sides ductive biology with standard socialization of a distribution. Typically, the outer 5% of explanations of human mating will a com- scores are eliminated, reflecting the view in prehensive theory of sex differences be pos- the social sciences that the outer 5% of sible (e.g., Geary, 1998; Mealey, 2000). At scores may be significantly different from present, because our findings reside amid a the true mean. In accordance with the rec- vast array of empirical studies supporting ommendations of Rosenthal and Rosnow, the theory of parental investment (includ- we eliminated from consideration the outer ing decades of research on nonhuman ani- 5% of participants based on their responses mals), we believe our evolutionary explana- to the “lifetime” scale of the Number of tion of sex differences in the desire for Partners measure. This was done within sexual variety is the most parsimonious each sample by removing the top 2.5% and among alternate psychological hypotheses. the bottom 2.5% from the distributions of each sex. We also eliminated from our sta- Do male undergraduates prefer more sexual tistical analyses all participants who failed partners than female undergraduates? The to complete the “lifetime” scale from the second prediction from SST was that men Number of Partners measure. As a result, will desire larger numbers of sexual part- the final sample sizes for our statistical ners than women. To evaluate the replica- analyses involving trimmed means included bility of the empirical findings from Buss 69 men and 67 women from the Original 432 D. I? Schmitt et al. sample and 287 men and 644 women from proximately 14 sex partners in his lifetime, the Undergraduate sample. whereas the average woman wanted just A comparison of the number of part- over 2, t(929) = 7.20,~< .001. Even so, the ners desired by men and women in the Undergraduate male distributions had Original sample and the larger Under- standard deviations that were quite large. graduate sample is displayed in Figure 1. Further examinations of the male Under- The trimmed means for male and female graduate distribution revealed that even participants in the Original sample were after eliminating the most extreme scores, largely replicated in the Undergraduate the male distribution was still significantly sample. None of the male means from the skewed. This led us to consider using medi- Undergraduate sample were significantly ans to further evaluate whether men and different from the Original sample's male women differed significantly in the number means. Among women, the Undergraduate of partners they desire across future time sample reported desiring slightly fewer intervals. partners than the Original sample for the In the Original sample, the medians for time periods after the 6-Month interval. men and women were significantly different Hence, the only significant differences be- at every time interval. For example, over a tween the Original and Undergraduate participant's lifetime the median man de- samples were that Undergraduate women sired 9 sexual partners, whereas the median wanted fewer sex partners than the Origi- woman desired 3, x2(142) = 16.2, p < .001. nal women. The interpolated medians of men and As shown in the first two columns of Ta- women in the Undergraduate sample are ble 1,the sex differences in desire for sexual displayed down the right side of Table 1. partners found in the Original sample also Because the use of medians made unneces- were replicated in the large and geographi- sary the need to eliminate outliers, the re- cally diverse Undergraduate sample. The sults in Table 1 were based on the original average Undergraduate man wanted ap- sample sizes first reported in the Method

20

15-

10-

-Original Men Original Women -__Undergraduate Men Undergraduate Women

Time Figure 1. Trimmed mean number of sexual partners desired by men and women in the Original and Undergraduate samples at different time periods into the future. Desire for sexual variety 433

Table 1. Sex differences in the number of partners desired in the undergraduate sample

Trimmed Means Medians

Time Men Women t Men Women x2 1 Month 1.3 0.6 9.42*** 1.0 0.6 102.10** * (1.6) (0.6) (0.7) (0.6) 6 Months 1.9 0.7 9.21*** 1.3 0.7 154.88*** (3.1) (0.6) (0.9) (0.6) 1Year 2.8 0.9 9.59*** 1.6 0.9 177.05* * * (4.9) (0.7) (1.3) (0.5) 2 Years 4.2 1.1 8.82*** 1.9 1.o 135.46*** (8.7) (0.8) (1.8) (0.5) 3 Years 5.1 1.2 9.39*** 2.2 1.1 112.50*** (10.4) (1.0) (2.0) (0.5) 4 Years 6.0 1.4 9.33*** 2.4 1.2 87.95*** (12.4) (1.1) (2.4) (0.7) 5 Years 7.0 1.5 9.39*** 3.0 1.3 78.12* * * (14.5) (1.3) (2.8) (0.7) 10 Years 9.1 1.7 8.39*** 3.6 1.4 76.78* * * (21.9) (1.6) (3.8) (0.8) 20 Years 11.2 1.8 6.32*** 3.6 1.4 69.65*** (37.4) (1.7) (4.3) (0.9) 30 Years 12.4 1.9 6.45*** 3.8 1.4 70.06*** (40.8) (1.8) (4.6) (0.9) Lifetime 14.2 2.1 7.20*** 4.0 1.5 54.26*** (42.7) (2.0) (4.8) (1.1)

Note: Means reported in this table were trimmed means (Rosenthal & Rothnow, 1991) from a sample of 287 men and 694 women. The standard deviation of each mean is reported in parentheses below the mean. The r-values represent the significance of sex differences between trimmed means. The medians reported were in- terpolated from the distributions of 339 men and 710 women. The Interquartile Range (Q) for each distribu- tion is presented in parentheses below each median. The x2 statistics were computed using the Median Test command from SPSS, uninterpolated medians were used in the Median Tests. *** = p < .001.

section. As shown down the second set of (e.g., number of partners desired in a life- columns of Table 1, the medians for men time, K-S Z = 4.95, p < .001). In short, and women in the Undergraduate sample although the median number of partners were significantly different for every time desired was less than the mean for all time interval. For example, over a participant’s intervals and for both sexes, the differences lifetime the median Undergraduate man between men and women in their desires for desired 4 sexual partners, whereas the me- large numbers of sex partners persisted dian woman desired 1.5, x2(977) = 54.26,~ whether trimmed means, medians, or distri- < .001. butions were analyzed. Indeed, Miller and The interquartile ranges for the sexes, Fishkin (1997) reported that male and fe- listed below each median in Table 1, also male medians were significantly different in suggested that the male and female distri- their study using the Number of Partners butions diverged in a robust manner. For measure. example, the 75th percentile for Under- Finally, we examined whether the num- graduate men was at about 9 sex partners in ber of partners desired by men and women a lifetime, whereas for women the 75th per- in the Undergraduate sample were signifi- centile was less than 3 partners. In addition, cantly different from one. In men, the num- Kolmogorov-Smirnov tests for differences ber of partners desired was significantly in the distributions of male and female de- higher than one for all time periods, ranging sires for sexual variety were also significant from 1Month, t(286) = 2.88,~< .01, to an 434 D. fl Schmitt et al. entire Lifetime, t(286) = 5.25, p < .001. In From these results we can conclude that addition, the median number of partners de- college-aged men and women, on average, sired by men in lifetime was 4.0. Although tend to express desires for more than one the modal number of partners desired in a mating partner. Moreover, men tend to ex- lifetime was 1, over 58% of men reported a press this preference more strongly, and desire for more than one mating partner in a more consistently, than women. Across all lifetime. For women, the number of partners subsamples from Texas to New York we desired was significantly less than one for found that men have a greater desire for sex- time periods ranging from 1Month, t(643) = ual variety than women. Indeed, using a -18.32,~< .001,to 1Year,t(643) = -3.49,~ similar set of measures, this pattern of results < .001. However, from the time period 2 was recently replicated in Germany (H.A. Years, (643) = 2.94, p < .01, to an entire Euler, personal communication, January 12, Lifetime, t(643) = 13.64, p < .001, women 2001).The robust nature of these results sug- did desire significantly more than one part- gests that the existence of a monomorphic ner. The median number of partners desired mating orientation-with almost all humans by women in a lifetime was 1.5. The modal possessing either long-term or short-term number of partners desired in a lifetime was reproductive strategies-is manifestly un- 1 for women, and 40% of women reported a likely. A large number of men (58%) and desire for more than one mating partner in a women (40%) preferred more than one lifetime. Figure 2 displays the complete dis- mating partner for a lifetime, which strongly tribution of male and female scores, using contradicts the hypothesis that most hu- the categories employed by Miller and mans are long-term sexual strategists. On Fishkin (1997) for extreme values. the other hand, a significant portion of men

70

60 c .-0 i-' 50 3

nL % 40 *ii 30 4-4c a, 2 20 Sex of Participant ea, I0 Men 0 ti Women

U Y- O 0 F Number of Partners Desired

Figure 2. Frequency distributions of the number of sexual partners desired by men and women in a lifetime, Undergraduate sample (latter frequencies are collapsed into categories). Desire for sexual variety 435 and women expressed a desire for only one time periods as assessed by the Time Known mating partner for a lifetime,suggesting that measure. some humans are devoted long-term maters. In the Original sample, men were signifi- Overall, these data are most consistent with cantly more likely than women to consider pluralistic evolutionary theories such as SST having sex with someone they viewed as de- (see also Gangestad and Simpson, 2000, for sirable after knowing the person for multi- an examination of the trade-offs that might ple time periods ranging from 1 Hour to 2 occur that lead men and women to actively Years. As displayed in Figure 3, the pattern pursue short-term versus long-term sexual of responses found in the Original sample strategies). Both men and women exhibited was confirmed in the Undergraduate sam- a wide range of mating desires, including ple. Moreover, the sex differences found in short-term and long-term temporal orienta- the Original sample also were replicated in tions; and men preferred a higher number of the Undergraduate sample. Unlike the sexual partners, an index of the desire for Original sample, the difference between sexual variety, than did women. men and women also was significant at the 5-Year interval in the Undergraduate sam- Do male undergraduates require less time ple, t(1043) = 3.43, p < .001. Across both before consenting to sex than female under- samples, the average woman considered graduates? The third prediction from SST having sex with someone they viewed as de- was that men will be willing to engage in sirable only after they had known the per- sexual intercourse after less time has son for about 6 Months, whereas the aver- elapsed than women. To test this prediction age man across samples considered having in a larger and somewhat more diverse sam- sex with someone they viewed as desirable ple, we performed independent t-tests com- after knowing the person for about 1Week. paring men’s mean level of sexual inter- Overall, the Time Known findings of course likelihood with women’s mean level Buss and Schmitt (1993), along with all the of sexual intercourse likelihood across all other findings of Buss and Schmitt, were

’”. \

Samples- Original Men __ ---Original Women ___Undergraduate Men Undergraduate Women

Time Known

Figure 3. Likelihood of consenting to sexual intercourse with a desirable person at different time periods into the future, reported by men and women; Original and Undergraduate samples. 436 D.F! Schmitt et al. replicated in Study 1 across a larger and was collected from a public university in more geographically diverse sample of par- Florida. This sample will be referred to as ticipants. At this point, it appears highly the “Mature” sample, and the average age likely that college-aged men desire sexual of participants was 39.9 years with a stand- variety significantly more than college- ard deviation of 7.9 years. No differences aged women. Most important, among mod- existed in age between men (M = 40.3) and ern evolutionary theories of human mating women (M = 39.6) in the Mature sample. it seems pluralistic theories such as SST Members of this sample participated in the best account for the robust nature of sex study for extra credit in a psychology course and individual differences in the desire for and were primarily middle-class and Cauca- sexual variety. sian.

Procedure. The Mature sample completed Study 2: The Desire for Sexual Variety in the same packet of measures adapted from a Mature Sample Buss and Schmitt (1993) described in Study The primary goal of Study 2 was to test the 1. This included the Time Known measure, three key sexual variety predictions from the Number of Partners measure, and the SST in an older and more mature sample of Currently Seeking measure. participants. Because previous studies have focused on young college undergraduates, it Results and discussion remains unknown whether sex differences in actively seeking short-term mates, in pre- Do older men seek short-term mates more ferring large numbers of sexual partners, or than older women? To evaluate whether in requiring less time to elapse before con- the sex differences in short-term mate seek- senting to sex might endure across the ing found in Study 1 were generalizable to lifespan. Women could become more en- older populations with more sexual experi- gaged in short-term mating over time, per- ence, we examined the levels of short-term haps because they gain self-confidence or seeking among men and women in the Ma- accrue material resources with age (cf. ture sample. The Mature sample provided a Townsend, 1993). Conversely,it has been ar- further replication of the sex difference in gued that men tend to become more long- short-term seeking uncovered by Buss and term oriented with more sexual experience Schmitt (1993),with men (M = 2.7) seeking and emotional maturity (Mathes, King, & short-term mates more than women (M = Miller, 1998). In either case, it is possible 1.5), t(186) = 4.71,~< .001. In addition, we that sex differences in the desire for sexual found the relative proportion of short-term variety substantially diminish over time. mate seeking was significantly higher in ma- Thus, the persistence of sex differences in ture men than mature women,t(184) = 3.40, short-term mating across mature samples p < .001. This sex difference once again dis- would constitute additional support for the played a moderate effect size (d = .50), fur- SST position that men’s natural short-term ther replicating the results of Study l. sexual psychology is anchored in the desire As displayed in Figure 4,there appeared for sexual variety. Finding significant sex to be a tendency for participants to report differences in the desire for sexual variety less interest in short-term mating as the age among older individuals would also provide of the sample increased, F(2,1345) = 32.06, evidence that monomorphic theories of hu- p < .001. It is possible that interest in short- man mating are unlikely to be correct. term mating generally decreases with age. For example, all post hoc Tukey HSD’s examining differences among the various Method samples were significant. That is, all samples Sample. A sample consisting of 83 men were significantly different across age and 109 women who were older than age 30 groupings. Perhaps older participants are Desire for sexual variety 437

Sex of Participantt

Men

0Women Original Undergraduate Mature

Samples

Figure 4. Mean level of seeking short-term mates reported by men and women; Origi- nal, Undergraduate, and Mature samples.

more likely to be married, and so their short- term mates. However, two findings stand term mate seeking was significantly attenu- out among the levels of long-term mate ated. It may also be that older participants seeking displayed in Figure 5. First, the Ma- experience a lower sex drive, and this lessens ture participants reported seeking long- their overall tendency to seek short-term term mates significantly less than the other mates. An alternate explanation of the sig- samples, F(1, 1343) = 105.34, p < ,001. It nificant differences among samples could seems likely that members of the Mature involve the fact that the Undergraduate and sample were already in marital relation- Mature samples were assessed after the on- ships and so were not in the midst of cur- set of AIDS awareness. The Original data rently seeking long-term mating partners. was collected in 1987, and research has Unfortunately, we failed to assess marital shown that sexual attitudes and behaviors of status in collecting data from either the Un- short-term mating were lessened by AIDS dergraduate or Mature samples. Second, awareness throughout the 1980s and early women in the Undergraduate sample (M = 1990s (Clark, 1990; Laumman, Gagnon, Mi- 4.5) reported seeking long-term mates sig- chael, & Michaels, 1994). With our current nificantly more than women in the Original methods, it is difficult to pinpoint precisely sample (M = 3.3),t(759) = -4.11,~< .001. why age differences exist in short-term mate We might speculate that women from the seeking. Nevertheless, in the current study, Undergraduate sample, who were an aver- mean-level sex differences in short-term age age of about 21 years and presumably mate seeking were replicated in an older near the end of their undergraduate educa- and presumably more sexually experienced tions, felt greater motivation for currently sample. seeking long-term mates than those from In the Mature sample, no sex differences the Original sample, who were about 19 were found in mean-levels of seeking long- years of age and near the beginning of their 438 D. f? Schmitt et al.

7.0

6.0 rn .-c Y 5.0 (I] a, -m 2 4.0 i 5 3.0 c 0 -I Sex of Participant 2.0 Men

1 .o CI]Women Original Undergraduate Maiure

Samples Figure 5. Mean level of seeking long-term mates reported by men and women; Original, Undergraduate, and Mature samples. college experiences. In sum, Prediction 1 For example, over a participant’s lifetime was strongly supported in a sample of older the median Mature man desired 1.8 sexual participants. partners, whereas the median woman de- sired 1.2. In addition, Kolmogorov-Smirnov Do older men prefer more sexual partners tests for differences in the distributions of than older women? The second prediction mature male and female desires were also from SST was that men will desire larger significant (e.g., number of partners desired numbers of sexual partners than will in a lifetime, K-S 2 = 1.95,~< .OOl). women. To evaluate the replicability of the We examined whether the number of empirical findings from Study 1 among partners desired by mature men and women older participants, we examined the extent were significantly different from one. In ma- to which sex differences existed in the ture men, the number of partners desired Number of Partners measure in the Mature was significantly higher than one for all time sample. As shown in the first two columns periods, ranging from 1 Month, 466) = 2.71, of Table 2, the significant sex differences in p < .01, to an entire Lifetime, 466) = 2.83,~ the desire for sexual partners found in the < .01. The median number of partners de- Original and Undergraduate samples were sired by men in a lifetime was 1.8. As with the replicated in the Mature sample. Using Undergraduate sample, although the modal trimmed means, with a sample of 67 men number of partners desired in a lifetime was and 99 women, the average Mature man 1,over 46% of mature men reported a desire wanted over 74 sex partners in his lifetime, for more than one mating partner in a life- whereas the average woman wanted 1.4. As time. For women, the number of partners presented down the right side of Table 2, desired was significantly less than one for the medians for men and women also were the time period of 1Month,t(98) = -3.61,~ significantly different at every time interval. < .001. However, from the time period 10 Desire for sexual variety 439

Table 2. Sex differences in the number of partners desired in the mature sample

Trimmed Means Medians

Time Men Women t Men Women X2 1 Month 2.1 0.8 3.72*** 1.2 0.8 13.03*** (3.4) (0.5) (0.7) (0.6) 6 Months 4.8 0.9 3.58*** 1.4 0.9 18.29*** (10.8) (0.5) (1.2) (0.6) 1Year 8.7 1.0 3.13** 1.5 1.o 21.39*** (24.2) (0.5) (1.4) (1.1) 2 Years 16.6 1.1 2.82** 1.6 1.1 15.32*** (54.0) (0.6) (2.1) (0.6) 3 Years 22.5 1.1 2.83** 1.6 1.1 18.01*** (74.3) (0.7) (2.3) (0.6) 4 Years 27.6 1.1 2.83** 1.7 1.1 16.55*** (91.9) (0.7) (2.5) (0.6) 5 Years 31.6 1.1 2.76** 1.7 1.1 17.50*** (107.6) (0.7) (2.8) (0.6) 10 Years 41.3 1.3 2.97** 1.7 1.2 11.73*** (132.1) (1.3) (3.3) (0.6) 20 Years 48.4 1.2 3.06** 1.7 1.2 14.88*** (151.1) (0.9) (4.8) (0.6) 30 Years 59.0 1.3 3.14** 1.7 1.2 10.10** (180.2) (1.O) (7.6) (0.6) Lifetime 74.1 1.4 3.43** * 1.8 1.2 10.12** (211.3) (1.3) (13.0) (0.6)

Note: Means reported in this table were trimmed means (Rosenthal & Rothnow, 1991) from a sample of 67 men and 99 women. The standard deviation of each mean is reported in parentheses below the mean. The t-values represent the significance of sex differences between trimmed means. The medians reported were in- terpolated from the distributions of 83 men and 109 women. The Interquartile Range (Q) for each distribution is presented in parentheses below each median. The x2 statistics were computed using the Median Test com- mand from SPSS, uninterpolated medians were used in the Median Tests. ** = p < .01, *** = p < .W1.

Years, t(98) = 2.31,~< .05, to an entire Life- the participants desired in 1 Day and 1 time, t(98) = 3.44,~< .001, women did de- Week. The Original sample’s Number of sire more than one partner. The median Partners measure started at the 1 Month number of partners desired by women in a interval. Because the number of sex part- lifetime was 1.2. The modal number of part- ners desired in 1 Day is likely less than the ners desired in a lifetime was 1 for women, number desired in 1 Month, the first item and over 25% of women reported a desire on the Number of Partners measure may for more than one mating partner in a life- have acted as an anchor from which partici- time. pants in the Mature and Undergraduate It should be noted that the medians in samples never adjusted (Tversky & Kahne- the Undergraduate and Mature samples man, 1974). were somewhat lower than in the Original sample. One possible explanation for the Do older men require less time before con- lower medians in the samples from Studies senting to sex than older women? The third 1 and 2 may involve the use of two new prediction from SST was that men will be scales in the Number of Partners measure. willing to engage in intercourse after less The Number of Partners measure com- time has elapsed than women. The pattern pleted by the Mature and Undergraduate of responses found in the Original and Un- samples asked how many sexual partners dergraduate samples was replicated in the 440 D. P. Schmitt et al.

Mature sample, as were the sex differences ual variety to counter the limitations inher- in the likelihood of consenting to sex at ent to self-report methodologies. various time intervals. Unlike the Original sample, the difference between men and Method women in likelihood of having sex with someone who was viewed as desirable after Sample. Study 3 included 24 men and 26 having known the person for 5 years was women from a medium-sized private uni- significant in the Mature sample, t(182) = versity in Illinois. This sample will be re- 2.24,~< .05. As with the Original and Un- ferred to as the “Observer” sample, and the dergraduate sample, the average Mature average age of participants was 20.5 years. woman considered having sex with some- Members of this sample participated in the one she viewed as desirable only after she study for extra-credit in a psychology course had known the person for about 6 Months, and were primarily middle-class and Cauca- whereas the average man across samples sian. considered having sex with someone he viewed as desirable after knowing them for Procedure. We had the Observer sample less than 1 Week. complete a packet of measures adapted Sex differences in the desire for sexual from Buss and Schmitt (1993) that were variety, originally reported in Buss and slightly different from those described in Schmitt (1993) and replicated in the larger Study 1.In this study, the participants did not sample of Study 1,were further documented complete the Currently Seeking measure. In in an older and more sexually experienced addition, the Time Known measure ranged sample in Study 2. Once again, among evolu- from 1 Minute to 5 Years, instead of 1 tionary theories of human mating, the plu- Minute to 10 Years; and participants had to ralistic theories such as SST seem most ca- rate the extent to which they perceived that pable of accounting for the observed sex “the average or typical” person of about differences in the desire for sexual variety. their age and of the opposite sex would con- sent to sex after having known someone over different periods of time. Finally, the Number of Partners measure completed by Study 3: The Desire for Sexual Variety as the Observer sample also asked what the Perceived by the Opposite Sex participants believed that the “average or Studies 1 and 2 employed self-report meas- typical” person of the opposite sex would ures of short-term mating desires to test the desire in terms of the ideal number of sexual three predictions from SST. Potentially, the partners over different time periods. The rat- sex differences from those studies derived ing scales of the Number of Partners and not from actual desires for sexual variety Time Known measure completed by the Ob- but rather from sex differences in the ten- server sample were identical to those used in dency to admit a desire for sexual variety. Studies 1 and 2. That is, women may have felt societal pres- sures not to report an interest in sexual vari- Results and discussion ety, and men may have for some reason felt the need to over-report their short-term According to the opposite sex, do men prefer mating desires. Although previous research more sexual partners than women? The suggests that in the context of anonymous second prediction from SST was that men surveys such response biases are largely at- will desire larger numbers of sexual partners tenuated (Andersen & Broffitt, 1988; Ca- than women. To evaluate the replicability of tania, McDermott, & Pollack, 1986),we con- the self-report findings from Buss and ducted an additional study to address these Schmitt (1993) using observer-report meth- concerns. In Study 3, we used observer- ods, we examined the extent to which men reports of men and women’s interest in sex- and women differed in their personal per- Desire for sexual variety 441

Table 3. Sex differences in the number of partners desired based on observer-reported perceptions of the opposite sex

Trimmed Means Medians

Time Men Women t Men Women X2 1 Month 2.0 3.26** 1.8 1.1 4.36* (1.2) (1.0) (0.6) 6 Months 3.6 3.22** 2.9 1.8 9.70** (2.9) (1.7) (1.3) 1 Year 6.0 3.17** 4.7 2.4 9.11** (5.5) (3.3) (0.8) 2 Years 9.5 2.63** 7.0 3.3 5.34* (10.6) (4.0) (1.3) 3 Years 13.8 2.18* 9.2 3.7 4.1 1* (20.6) (6.0) (1.9) 4 Years 15.8 2.40* 11.0 4.1 4.08* (20.9) (7.9) (2-4) 5 Years 17.6 2.52* 14.3 5.2 4.08* (21.8) (9.5) (2.7) 10 Years 20.3 2.70** 16.5 6.3 4.08* (23.4) (11.5) (2.7) 20 Years 21.9 2.77** 18.0 7.3 4.08" (24.5) (12.7) (2.9) 30 Years 24.2 2.94** 18.5 8.5 6.75** (25.8) (15.4) (3.3) Lifetime 27.5 2.94** 25.3 10.0 5.34* (27.6) (19.3) (4.7)

Note: Means reported in this table were trimmed means (Rosenthal & Rothnow, 1991) from a sample of 22 men and 22 women. The standard deviation of each mean is reported in parentheses below the mean. The r-values represent the significance of sex differences between trimmed means. The medians reported were in- terpolated from the distributions of 24 men and 26 women. The Interquartile Range @) for each distribution is presented in parentheses below each median. The x2 statistics were computed using the Median Test com- mand from SPSS; uninterpolated medians were used in the Median Tests. * = p < .05, ** = p < .01.

ceptions of the short-term mating desires of We examined whether the opposite-sex the opposite sex. As displayed in the first perceptions of the number of partners de- two columns of Table 3, the significant sex sired by men and women were significantly differences in the desire for multiple sexual different from one. The number of partners partners found in the Original, Undergradu- men were perceived to desire was signifi- ate, and Mature samples were replicated in cantly higher than one for all time periods, the Observer sample. Using trimmed means, except 1 Month. The median number of with a sample of 22 men and 22 women, partners perceived to be desired by men in women observed that the average man their lifetime was 25.3. Unlike in the Un- wants 27.5 sexual partners over his lifetime, dergraduate and Mature samples, the num- whereas men observed that the average ber of partners perceived to be desired by woman wants 9.9. As shown down the right men in a lifetime was multi-modal and side of Table 3, the medians for men and more than one. The first mode in men was women also were significantly different at 5,with 100% of women perceiving that men every time interval. For example, over a have a desire for more than one mating participant's lifetime the median man was partner in a lifetime. The number of part- perceived to desire 25.3 sexual partners, ners women were perceived to desire was whereas the median woman was perceived significantly higher than one for all time to desire 10.0. periods. Again, unlike the previous samples 442 D. P Schmitt et al. the number of partners in a lifetime was no sex differences were found at the 5-Year multi-modal, with the first mode at 5 and interval as well. Second, among the Ob- 100% of men perceiving that women have server ratings both men and women be- a desire for more than one mating partner lieved members of the opposite sex would in a lifetime. consent to sex more quickly than the Origi- nal, Undergraduate, and Mature samples in- According to the opposite sex, do men re- dicated. For example, women observed the quire less time before consenting to sex than average man would consent to sex with women? The third prediction from SST someone he viewed as desirable after only 1 was that men will be willing to engage in Evening, but the average Undergraduate sexual intercourse after less time has male reported that he would consent to sex elapsed than will women. The pattern of re- only after more than 1 Week had elapsed in sponses found in the Original, Undergradu- knowing the person. Although men and ate, and Mature samples were replicated in women perceived the opposite sex to be the Observer sample, as were the sex differ- more receptive to short-term sex than self- ences in the likelihood of consenting to sex reports would indicate, the sex differences at various time intervals. As shown in Table between men and women replicated using 4, there were two exceptions to this replica- observer-reported data sources. Overall, the tion. First, for the time periods of 2 and 5 Time Known and Number of Partners find- Years, the Observer sample did not provide ings of Buss and Schmitt (1993) were repli- significant sex differences in the likelihood cated using the observer-report sample in of consenting to sex. In the Original sample, Study 3.

Table 4. Sex differences in the time needed before consenting to sex across three samples

Undergraduate Sample Mature Sample Observer Sample

Time Men Women t Men Women t Men Women t 1 Hour 14.66*** -0.9 -2.6 6.51*** -0.2 -2.1 3.97*** (2.4) (1.1) (2.1) (1.1) 1 Evening 15.98*** -0.4 -2.3 6.71*** 0.6 -1.7 4.84*** (2.4) (1.5) (2.0) (1.4) 1 Day 16.71*** -0.2 -2.2 6.78*** 0.7 -1.5 4.64*** (2.4) (1.5) (2.0) (1.3) 1 Week 18.31*** 0.3 -1.8 6.93*** 1.2 -0.4 3.35** (2.2) (1.8) (1.9) (1.5) 1 Month 13.80** * 0.9 -1.0 5.86*** 2.0 0.4 3.95* * * (2.2) (2.1) (1.4) (1.4) 3 Months 13.80*** 1.3 -0.3 4.85 * * * 2.2 1.o 3.70*** (2.1) (2.2) (1.0) (1.3) 6 Months 11.57*** 1.7 0.4 4.20*** 2.3 1.4 3.25** (1.9) (2.0) (1.0) (1.0) 1 Year 8.95*** 2.0 1.1 3.25 * * * 2.4 1.9 2.03* (1.7) (1.9) (0.9) (0.7) 2 Years 6.95*** 2.0 1.3 2.96** 2.2 1.9 0.96 (1.6) (1.9) (1.2) (1.1) 5 Years 3.43** * 2.2 1.6 2.24* 2.0 1.9 0.28 (1.5) (1.7) (1.5) (1.5)

Note: Means were calculated based on the responses of 339 men and 710 women from the Undergraduate sam- ple, 83 men and 109 women from the Mature sample, and 24 men and 26 women from the Observer sample. The standard deviation of each mean is reported in parentheses below the mean. The t-values represent the significance of sex differences between means. * = p < .05, ** = p < .01, *** = p < .001. Desire .for sexual variety 443

Study 4: The Desire for Sexual Variety ing diversity, and why are men and women Linked to Psychological- Traits significantly different when it comes to the desire for sexual variety? From Studies 1 through 3, it appears that a According to Miller and Fishkin (1997), substantial number of people express de- one explanation of the observed set of plu- sires for short-term mating. Many men and ralistic findings might be that all humans are women actively seek short-term mates, re- naturally designed to be long-term mating quire little time before consenting to sex, strategists, but that modern environments and ideally desire multiple mating partners have caused large numbers of people in our at various time periods in the future. It is samples to have experienced unstable also clear from the present studies that men, forms of child development: “We would ar- on average, tend to desire sexual variety and gue that although short-term mating strate- short-term mating experiences more than gies may be fall-out from a failure of hu- women. Although heterosexual men and mans to interface with their adapted for women must, on average, behaviorally en- environments, seeking a long-term mate for gage in short-term relationships at the same a close enduring relationship is based in uni- rate given equal sex-ratios (Symons, 1979), versal design features (i.e., part of our evo- the psychological desire for sexual variety lutionary heritage)” (p. 228-229). Thus, when pursuing short-term sex seems pri- “current behavioral variability, including marily a male phenomenon. This is true re- differences between men and women, may gardless of the sample, the data source, or well be the result of relatively modern dif- the statistical techniques used to evaluate ferences in the social environments encoun- this prediction. Most pluralistic theories tered by humans that were not present in that explain human mating strategies as the Pleistocene era” (p. 199). In other words, naturally diverse and variable both within modern parenting and socialization prac- and between the sexes are fully capable of tices, with boys presumably receiving less accounting for this finding. “adapted for” parenting and socialization For example, people may behaviorally than girls, may have precipitated the sex and pursue different mating strategies depend- individual differences in desires for sexual ing on their own mate values, the local sex- variety evident in Studies 1through 3. ratio, and other ecological sources of in- If this were the case, those individuals formation (see Buss, 1994; Gangestad & who responded to the Time Known and Simpson, 2000; Low, 2000). According to Number of Partner measures with more de- SST (Buss & Schmitt, 1993), between-sex sire for sexual variety may possess a trait- variability in the context of short-term mat- like tendency toward short-term mating ing exists because the male short-term psy- anchored in an interpersonal history of chology is designed to be dominated by the poor parental attachment. It has been docu- desire for sexual variety, whereas female mented that people who possess insecure short-term psychology is designed to be attachment styles also tend to possess at- guided by desires for men who possess su- tributes suggestive of a short-term mating perior levels of status, resources, or genetic strategy, such as engaging in one night quality. Theories that posit a monomorphi- stands and feeling a lack of trust with their cally designed mating strategy among hu- current dating partners (Brennan & Shaver, mans (e.g., Fisher, 1992; Miller & Fishkin, 1995; Simpson, 1990). Moreover, children 1997; Zeifman & Hazan, 1997) may find it who possess secure attachment styles seem more difficult to account for the magnitude to mature into monogamous adults (Hazan of sex and individual differences found in & Zeifman, 1999). the desire for sexual variety. If human be- If short-term mating is deeply rooted in ings have been designed to pursue only one developmental dysfunction, then both inse- mating strategy, why is there so much mat- cure attachment and the desire for sexual 444 D. I? Schmitt et al. variety should be further associated with short-term in nature, and . . . may foster broad indexes of adult psychological dys- early and frequent conceptions (or at least function. Theoretically, insecure children would have done so in some EEAs)” (p. develop a negative sense of themselves and 155). a negative sense of others (Bartholomew & In this view, insecure attachment styles Horowitz, 1991). Consistent with the origi- may lead to unstable romantic relationships, nal ethological model of attachment pro- but this specific form of relationship func- posed by Bowlby (1969/1982), these nega- tioning may have been adaptive in many in- tive “internal working models” of attitudes stances in our ancestral past. Today, when toward oneself and others then persist into insecure attachment develops into short- adulthood. Eventually, a basic lack of self- term mating, this may be what is most adap- worth and fundamental distrust of others tive in a given reproductive context; this is causes high levels of anxiety and an avoid- what our attachment system is designed to ance of interpersonal closeness (Simpson, do (Belsky, 1999; Chisholm, 1996). In addi- Rholes, & Nelligan, 1992). Indeed, those tion, insecure attachment is seen as only one who possess insecure attachment styles as contributing factor to the development of adults are at higher risk for a broad range of short-term mating, along side other factors social psychological pathology, including such as the local pathogen prevalence, op- affective, antisocial, and borderline person- erational sex-ratio, and the relative mate ality disorders (for a review see Dozier, value of mating participants (Buss & Stovall, & Albus, 1999). In this view, short- Schmitt, 1993;Gangestad & Simpson, 2000). term mating is one consequence of a funda- Thus, short-term mating may be related to mental failure in our normative long-term some forms of relationship instability but attachment system, a failure that should may prove generally unrelated to the broad have profound and widespread conse- levels of psychological dysfunction associ- quences for reproduction, mental health, ated with insecure attachment. Short-term and smial psychological functioning. mating need not be psychologically nor re- Other attachment theorists have posited productively maladaptive according to the that a short-term mating psychology may pluralistic view of attachment. result from key developmental experiences One way to evaluate the relative merit of but have focused on the limited relation- these countervailing positions on the desire ship between attachment and short-term for sexual variety, the pursuit of short-term mating, as well as the potential adaptive mating strategies, and the relative function- nature of insecure attachments (e.g., Kirk- ality of differing attachment styles would be patrick, 1998). These pluralistic “life-his- to formally examine the empirical linkages tory” approaches emphasize the facultative, between these constructs and measures of context-dependent nature of our species- psychological health and interpersonal typical attachment system, a system that functioning, especially those variables out- may contribute, at times, to functional side of the specific realm of romantic rela- short-term mating desires (Burton, 1990; tionships (since short-term mating can be Chisholm, 1996). Lancaster (1989), for ex- operationally defined as romantic relation- ample, has speculated that short-term mat- ship “dysfunction”). As Belsky (1999) notes, ing may be functional for women in cul- what little research has been done on this tures where their pool of viable long-term topic tends to support pluralistic attach- partners becomes restricted. Others have ment approaches: “Although no research on provided detailed rationale for how inse- the sequelae and correlates of attachment cure attachment styles may be manifesta- (in childhood or adulthood) has been stimu- tions of an opportunistic, short-term repro- lated by such a life history perspective, data ductive strategy (Draper & Harpending, that have been gathered on mating and par- 1982). Belsky (1999) notes that insecure at- enting are rather consistent with such theo- tachment styles “can be expected to be rizing” (p. 254). Still, no research has speci- Desire for sexual variety 445 fically examined whether the desire for sex- short-term mating. This was the Sociosexual ual variety, per se, is related to the chronic Orientation Inventory (SOI: Simpson & pursuit of short-term mating strategies, in- Gangestad, 1991), a standard instrument secure attachment styles, and psychological used to assess long-term versus short-term health in ways that differentiate among plu- mating strategies. A second measure was in- ralistic and monomorphic positions on basic cluded to assess attachment styles, the Rela- human mating strategies. tionship Questionnaire (Bartholomew & If it were found that the desire for sexual Horowitz, 1991). variety and insecure attachment were Six basic psychological indexes that have strongly and similarly linked to poor mental been shown to be related to mental health health and general social dysfunction, then and social functioning were then completed monomorphic theories that claim short- by the participants. First, a measure of term mating is primarily the maladaptive af- global personality traits (Goldberg, 1992) termath of insecure attachment would merit was administered. This measure contains serious consideration. However, if the desire two scales strongly related to psychological for sexual variety and insecure attachment health-Neuroticism and Openness to Ex- were not similarly related to mental health perience. The Neuroticism scale is posi- and social dysfunction, the perspective of tively related to virtually all personality dis- monomorphic monogamy as our natural orders and susceptibilities to disease (Costa mating system would not be supported. In- & Widiger, 1994; Strack & Lorr, 1994) and stead, evidence would be provided that is conceptually anchored in anxiety, depres- short-term mating may be a functional mat- sion, and vulnerability to stress. Openness ing strategy, relatively independent of the to Experience, on the other hand, is posi- nonrelationship psychopathology broadly tively related to self-awareness, creativity, associated with insecure attachment. Study and depth of emotional experience (Mc- 4 was conducted to examine the degree to Crae & Costa, 1997), all indicators of psy- which the desire for sexual variety is linked chological health and adjustment. A meas- to the chronic pursuit of short-term mating ure of erotophobia-erotophilia known as strategies and adult romantic attachment the Sexual Opinion Survey (Fisher, Byrne, styles and whether the desire for sexual vari- White, & Kelley, 1988) was then completed. ety is further associated with indexes of ba- Erotophilia has long been associated with sic mental health and social functioning. physically and psychologically healthy sex- ual attitudes and behavior (Fisher et al., 1988). A measure of healthy sexual atti- Method tudes (e.g., willingness to use condoms) was Sample. The participants in this study were also administered (Gough, 1973). A meas- 68 men and 99 women from a medium-sized ure of self-esteem called the California private university in Illinois.Members of the Self-Evaluation Scales (Phinney & Gough, sample participated for extra credit in hu- 1984) was completed by the participants. In man sexuality or motivation courses, and some studies, low levels of self-esteem have were primarily middle-class and Caucasian. been associated with psychological ill- health, poor social skills, and sexual permis- Procedure. All participants were presented siveness (Baumeister, 1997; Perlman, 1974). with a packet of measures entitled “The Per- Finally, a measure of social desirability sonality and Sexuality Anonymous Ques- called the Marlowe-Crowne Social Desir- tionnaire Study.” The packet first contained ability Scale (Crowne, 1979) was adminis- the Time Known and Number of Partners tered. High levels of social desirability have measures used in the preceding studies. Par- recently been linked with the tendency to ticipants then completed a measure de- distort one’s social self-presentation in a signed to assess whether the desire for sex- way indicative of relatively severe psycho- ual variety is related to trait-like levels of pathology (see Robins & John, 1997). 446 D. R Schmitt et al.

Results and discussion large- numbers of sexual partners tended to have dismissive attachment styles. For The patterns of sex differences found in women, those who reported a restricted so- Studies 1through 3 were replicated in Study ciosexual orientation tended to exhibit a se- 4. Men expressed a desire for significantly cure attachment style. Women who re- larger numbers of sex partners at various ported that they would require more time points in the future than did women. Men before consenting to sex tended to exhibit a required significantly less time to elapse be- fearful attachment style. Although Study 4 fore consenting to sex than did women. For provided evidence that the desire for sexual economy of presentation purposes, overall variety is moderately related to disposi- composite scores for the Number of Part- tional levels of short-term mating strategies ners and Time Known measures were cre- and somewhat related to insecure attach- ated. Each composite score consisted of the ment styles, it remains unclear whether this mean average score across the time inter- concert of variables represents maladaptive vals within each measure. The t-tests for sex dysfunctions of our natural long-term mat- differences on all measures and composite ing system or viable alternative mating scores of sexual variety desires, sociosexual- strategies. ity, and attachment are presented along the diagonal of Table 5. Are desires for sexual variety, short-term mating strategies, and adult attachment styles Is the desire for sexual variety linked with linked with indexes of psychological well- short-term mating tendencies and insecure being? As seen in Table 6, we found that attachment? As seen in Table 5, the com- desires for sexual variety and sociosexuality posites of desire for sexual variety corre- were largely unrelated to indexes of mental lated positively with chronic short-term health. Among men and women, those who mating as indexed by the SO1 (Simpson & expressed desires for sexual variety did not Gangestad, 1991), with high scores indicat- possess low self-esteem, emotional instabil- ing a more short-term, unrestricted mating ity, low openness to experience, or distort orientation. Among both men and women, their self-presentations in a socially desir- sociosexuality correlated significantly with able manner. Indeed, men who preferred the Number of Partners composite and with larger numbers of sex partners, r(66) = the Time Known composite. In other words, + 0.29,~< .05, and possessed unrestricted those who possessed an unrestricted so- sociosexual orientations, r(66) = f0.31,~< ciosexual orientation desired larger num- .01, tended to have higher self-esteem. bers of sex partners over time and required Those men likely to consent to sex with less time before consenting to sex. It ap- someone after knowing them for a short peared, therefore, that current desires for period of time were more emotionally sta- sexual variety as measured with the ble, and men who desired sexual variety Number of Partners and Time Known com- were more likely to be open to new experi- posite scores were significantly related to ences, a trait associated with being intellec- the more chronic pursuit of short-term mat- tual, cultured, and self-aware (McCrae & ing strategies. Costa, 1997)-a11 indicators of positive life Previous research has indicated that adjustment. Men and women who reported those who follow a short-term mating strat- that they would have sex more quickly than egy tend to possess insecure attachment others tended to report higher levels of ero- styles (e.g., Simpson, 1990). We confirmed tophilia, a known correlate of sexual health that adult attachment styles were signifi- and well-being (Fisher et al., 1988), and cantly related to mating strategies, espe- short-term oriented men reported that they cially among men. For example, men who would be willing to follow safe sex prac- possessed an unrestricted sociosexual ori- tices. entation and those who preferred to have Overall, the results from Study 4 suggest Table 5. Intercorrelationsand sexdifferences among the desirefor sexual variety, sociosexuality, and adult romanticattachment styles in Study4

The Desire for Sexual Variety

Number Attachment Styles of Time Partners Known Sociosexuality Secure Dismis. Preocc. Fearful $ Numberof partners (4.58***) .53*** .44*** - .25* .26* .02 .31** Time known .08 (9.49***) .39*** -.15 .03 .12 .04 Sociosexuality .31** .27** (5.48** *) - .09 .29* - .05 .16 Secure - .02 -.11 - .20* (-2.41*) - .34** - .34** -,52*** Dismissive .05 - .01 .08 -.19 (1.61) .03 .12 Preoccupied .04 -.13 .13 - .23* - .24* (2.26") .32** Fearful - .04 -.33*** - .01 -.35*** .15 .19 (0.86)

Note: Correlations reported above the diagonal were based on the responses of 68 men; correlations reported below the diagonal were based on the responses of 99 women. The t-tests for sex differences in scale means are represented along the diagonal, with positive i-values indicating men scored higher on the scale and negative r-values indicating women scored higher on the scale. * = p < .05, ** = p < .01, *** = p < .001. Table 6. The desire for sexual variety,sociosexuaIity, andadult romantic attachment styles correlated withpsychological well-being and sexual health

The Desire for SexualVariety

Number Attachment Styles of Time Partners Known Sociosexuality Secure Dismis. Preocc. Fearful

PsychologicalWell- Being Self-esteem: Men .29* .10 .31** .05 .16 -.17 -.11 Women .04 - .01 -.13 .05 .16 -.31** .06 Emotional stability: p Men .13 .26* .16 .05 .09 -.14 - .26* & Women .09 - .01 -.14 .10 .26** -.28** - .08 Opennessto experience: Men .33** .29* .19 .05 .14 .15 - .03 Women -.12 -.16 -.12 .06 - .23* .11 - .01 Social desirability: Men - .08 - .06 - .06 - .34** .24* .28* -23 Women .02 - $26 .oo - .03 -.30** .16 .oo SexualHealth Erotophilia: Men .47*** *47*** .53*** -.lo .35*" .15 .09 Women .05 .29** .25** -.25"* -.17 .02 -.11 Safe sex practices: Men .10 .31** .41*** -.11 .21 .14 - .23 Women -.11 - .08 - .09 .21* .14 - .17 .04

Note: Analyses based on 68 men and 99 women from Study 4. * = p < .05, ** = p < .01, *** = p < ,001 Desire for sexual variety 449 that the desire for short-term sexual variety and the basic indexes of mental and social was not indicative of psychological dysfunc- dysfunction that typify insecure attachment. tion or poor mental health. If anything, it In men, the short-term mating desire for sex- was indicative of positive mental health, at ual variety may actually be linked to positive least among men. This apparent sex differ- aspects of mental health. ence may be explained by the fact that men, These findings appear to contradict the but not women, who actively seek sexual va- perspective that short-term mating repre- riety are pursuing and to some degree satis- sents a maladaptation of the singular long- fying (based on unrestricted behavioral SO1 term mating system in humans. Although it scores) a key tactical objective of their seems possible that extremely abusive and short-term mating strategy (Buss & Schmitt, unstable juvenile environments may cause 1993).However, with our current methods it some forms of insecure attachment that in- is difficult to pinpoint whether pursuing sex- tersect with promiscuity and short-term ual variety leads to feelings of psychological mating, it may be legitimate to view such health in men, or whether those men who cases as alternative mating strategies, espe- are psychologically healthy tend to pursue cially suited to unstable reproductive envi- short-term mating via sexual variety. ronments (e.g., Ellis, McFadyen-Ketchum, The relationships between attachment Dodge, Pettit, & Bates, 1999; Lancaster, styles and psychological health corrobo- 1989). Clearly, more data will be needed to rated previous research showing that in- disentangle the issue of whether insecure at- secure attachment is associated with poor tachment is a definitive cause of short-term mental health and social dysfunction. mating strategies, whether it simply tends to Women who were preoccupied did tend to coincide with particular forms of short-term possess low self-esteem, r(97) = -0.31,~< mating, or whether it is a functionally inde- .01. Women who were emotionally unstable pendent system for regulating negative af- tended to possess preoccupied, but not dis- fect in interpersonal relationships (see missive, attachment styles. Men who were Schmitt, 2001). The results from the present low on secure attachment, high on dismis- study, however, confirm that although inse- sive, and high on fearful, as well as women cure attachment styles are linked to poor who were low on dismissive, also tended to mental health, attachment-related mental distort their self-presentation in a socially- dysfunction is largely independent of the desirable manner. Finally, women who were more basic desire for sexual variety and the low on secure attachment and men who pursuit of short-term mateships. were dismissive tended to possess un- healthy sexual attitudes. Are attachment styles more important than This overall portrait of short-term sexual gender in explaining short-term mating de- desire and romantic attachment seems to sires? It has been argued that environ- suggest that, although short-term desires mental factors such as parental caregiving and insecure attachments are weakly re- and attachment styles are more important lated to one another, the dysfunctional men- than gender in explaining extant short-term tal health aspects of insecure attachment are mating desires (Miller & Fishkin, 1997, p. completely unrelated to short-term mating 225). That is, the reason men may more ac- desires. In other words, whereas attachment tively seek short-term mates is because they and short-term mating may overlap concep- have poorer relationships with their parents tually and empirically, the social and mental and develop more insecure attachment dysfunction components of insecure attach- styles as adults than do women, not because ment appear not to overlap with short-term men are strategically designed to seek sex- desires for sexual variety. Thus, the pivotal ual variety when pursuing short-term mates. finding of Study 4 is that, in normal samples We attempted to conceptually replicate pre- of people, there appears to be no systematic vious findings that showed once attachment link between the desire for sexual variety styles were accounted for, neither gender 450 D.P Schmitt et al. nor interactions of gender and attachment before consenting to sex than do women, significantly predicted short-term mating and the desire for sexual variety results from desires (Miller & Fishkin, 1997). We were a dispositional short-term mating tendency unable to replicate these findings using our that does not flow from poor mental health present set of measures. In fact, we found or social dysfunction. The first three findings that gender predicted short-term mating de- proved to be robust across samples differing sires after attachment styles were partialed in age. They proved robust across samples out, but attachment styles did not predict differing in geographical location. They short-term mating after gender was par- proved robust across different methods. tialed out. This was true when predicting the And they proved robust when various sta- Number of Partners composite, the Time tistical procedures were used to control for Known composite, and SO1 scores. the influence of outliers and distributional One possibility for this replicatory fail- skewness.These findings support the propo- ure is that Miller and Fishkin (1997) tried to sition that, although men and women both predict short-term mate seeking and in- have short-term mating as one component cluded retrospective measures of parental of their menu of mating strategies, men caregiving in their analyses, whereas we did clearly differ from women in their short- not. Even so, the likely possibility that gen- term desire for sexual variety. der interacts with parental caregiving and These findings may have important im- attachment formation early in life (i.e., the plications for romantic processes in close re- emergent adaptations of developing boys lationships. First, sex differences in the de- may evoke parental environments that sire for sexual variety may help to explain cause harsh socialization and insecure at- some recurring forms of sexual conflict, tachment; see Geary, 1998 for a review) such as conflict over the frequency of sexual makes it extremely difficult to make defini- intercourse (Buss, 1989; Hurlbert & Apt, tive claims about the superiority of environ- 1994). Second, improving our understand- mental factors over gender in explaining ing of why the sexes differ in short-term sex- the desire for sexual variety. Instead, we ual desire may have important implications would caution as noted above that more for sex and marital therapy (Kaplan & data will be needed to disentangle the issue Sager, 1971; Verhulst & Heiman, 1988). We of how insecure attachment is causally as- have presented a portrait of romantic func- sociated with short-term mating strategies tioning that suggests poor relationship out- (see also Kirkpatrick, 1998). The limited comes may result from a mismatch of stra- conclusion we can make based on Study 4 tegic interests and not from unhealthy is that any empirical overlap that exists be- relationship dynamics, per se. That is, those tween insecure attachment and short-term individuals that are insecurely attached and mating is unrelated to the poor mental suffer relationship instability and a lack of health frequently associated with insecure closeness may be pursuing a strategic sex- attachment. uality that is individually functional but yields poor long-term relationship out- comes. Future research on the elicitors of General Discussion this functional short-term strategizing (e.g., The purpose of this research was to test four Gangestad & Simpson, 2000) may help key predictions from Sexual Strategies The- identify when relationship instability results ory (SST) that differentiate it from compet- from interpersonal difficulties and when re- ing theories of human mating. Evidence lationship instability is to be expected as from four studies confirmed the SST predic- part of an individual’s reproductive strategy. tions that men actively seek short-term mat- Again, an important contribution of this re- ing relationships more than women, men search is that the desire for sexual variety prefer larger numbers of sexual partners seems unrelated to psychological dysfunc- than women, men require less time to elapse tion and may well be an alternate mating Desire for sexual variety 45 1 strategy grounded in a long history of repro- more attractive and fall in love more ductive success. quickly (Rubin, Peplau, & Hill, 1981), and Previous research on sex differences in anticipate greater willingness to engage in romantic relationships essentially cor- short-term sex (Surbey & Conohan, 2000) roborates our main empirical findings. For all corroborate Prediction 3 from SST. If example, the findings that men relax their women desired sexual variety and required minimum mate preference standards in less time before consenting to sex, they, too, short-term mating contexts implies that they should tend to perceive sexual interest from are more interested in carrying out short- strangers, fall in love quickly, and anticipate term relationships (Kenrick et al., 1990).The great willingness to engage in short-term finding that men seek extra-marital affairs sex. Based on the accumulated evidence, more than women (Buss, 2000; Laumman et generally women do none of these things. al., 1994) bolsters the notion that men seek The findings that men prefer more sexually short-term relationships more than women. permissive dates than women (Oliver & The fact that gay men have affairs more than Sedikides, 1992), that men but not women do lesbians (Blumstein & Schwartz, 1983) have their short-term romantic desires ex- also corroborates our finding that men seek perimentally elicited by interacting with a short-term mates more than women. Predic- sexually accessible target of the opposite tion 1 from SST was strongly supported in sex (Schmitt, Couden, & Baker, 2001), and the current set of studies, and many other that men actually do consent to sex with findings provide a powerful confluence of strangers more often than women (Clark & evidence that men seek short-term mating, Hatfield, 1989) support our findings that in almost all its forms, more than women. men’s short-term mating psychology is Research showing that men more than based, in part, on the tendency to require women sexually fantasize about multiple little time to elapse before consenting to sex partners (Ellis & Symons, 1990) sup- sex. ports Prediction 2 from SST that men pre- The above findings testify to the fact that fer larger numbers of sex partners than short-term mating is a fundamental compo- women, as does the fact that men seek out nent of the human sexual strategy reper- more prostitutes than women (Bess & toire. If it were true that short-term matings Janus, 1976), that gay men have more nu- were essentially abnormal deviations from merous sex partners than lesbians (Ruse, our common human nature, then Blumstein 1988), and that men consume more pornog- and Schwartz’s (1983) finding that “virtu- raphy containing multiple partners (Mala- ally all gay men have other sexual partners” muth, 1996). Again, it is not that women (p. 275), whereas “for lesbians, sex outside never seek nor fantasize about short-term the relationship is often an isolated event” mating. Women’s romance novels, for ex- (p. 277) would suggest that most gay men ample, are among the highest selling books are insecurely attached and on an emo- in the world and often contain stories of tional-developmental trajectory toward women engaged in short-term mating (Ellis short-term mating. We consider the validity & Symons, 1990). However, this form of of such a characterization of gay men to be short-term mating usually does not involve highly dubious. Research suggests that gay sex with a variety of partners. Instead, such men are, in fact, very similar to heterosex- novels typically center around men who ual men in their mating psychology (Bailey, have high status or possess desirable ge- Gaulin, Agyei, & Gladue, 1994; Weinrich, netic qualities, attributes that women adap- 1987), including a short-term mating psy- tively prefer in short-term mates (Buss & chology guided by the desire for sexual va- Schmitt, 1993; Ellis, 1992). riety as outlined by SST. The reason gay Research showing that men more than men are more actively engaged in short- women perceive sexual interest from term mating than lesbians is likely because strangers (Abbey, 1982), find first dates their mating partners are other men, who 452 D.I? Schmitt et al.

also have a short-term psychology guided men could not express their desire for short- by normal desires for a large number of term mating if there were no willing women sexual partners not because most gay men (Greiling & Buss, 2000). Given the costs to are interpersonally and emotionally inse- women associated with short-term mating cure. (e.g., untimely pregnancy, reputational dam- These findings, in conjunction with those age), it would be surprising if women recur- of researchers studying different contexts rently engaged in short-term mating unless of human mating (Clark, Shaver, & Abra- they reaped adaptive benefits that out- hams, 1999; Regan, 1998), in different cul- weighed the costs. Evidence is cumulating tures (Knodel, Low, Saengtienchai, & Lu- that women do reap predictable benefits cas, 1997; Walter, 1997), and using different from short-term mating in certain contexts research methods (Hassebrauck, 1998; (Gangestad & Thornhill, 1997), that short- Speed & Gangestad, 1997; Weiderman & term reproductive strategies exist in many Dubois, 1998), including experimental de- different cultures (Draper & Harpending, signs (Schmitt, Couden, & Baker, 2001), ap- 1982), and that humans possess physiologi- pear to flatly contradict several alternative cal adaptations indicative of short-term theories of human mating that have been mating strategies (Baker & Bellis, 1995; proposed over the past decade. First, the Mdler, 1988). Thus, at times some women findings falsify theories that postulate that and men may adaptively select casual sex men and women are monomorphic with re- from their mating menu in certain contexts. spect to their mating strategies. Men and Neither all men nor all women can be accu- women clearly differ in the prominence of rately described as designed for exclusive the short-term component of their mating long-term monogamy. strategies, whether assessed through the ex- Both sexes appear to have evolved short- pressed desire for casual sex, the number of term and long-term sexual strategies, as pos- partners they want, or the time needed to ited by SST (Buss & Schmitt, 1993) and elapse before consenting to sex. Theories many other pluralistic approaches to human that posit sexually monomorphic mating mating (e.g., Gangestad & Simpson, 2000). strategies (e.g., Fisher, 1992; Miller & Theoretical attempts to simplify this com- Fishkin, 1997; Silverstein, 1996) cannot eas- plex account by positing either that the ily account for these data. sexes are identical in their mating strategies Second, the findings falsify theories that or that humans have only a singular long- postulate that women and men alike have term mating strategy cannot account for the evolved solely and exclusively for long-term cumulative empirical findings. Often in committed mating (e.g., Miller & Fishkin, social science, theories are insufficiently- 1997;Zeifman & Hazan, 1997).The number responsive to empirical findings. In the of partners desired in a lifetime exceeds one current case, the findings on the various for both sexes, even when outliers are re- components of the desire for sexual variety moved, when medians rather than means are sufficiently robust and consistent that are examined and when different methods theories inconsistent with them need to be are used to assess this desire. Theoretically, substantially modified or jettisoned.

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